The positive and negative power supplies (MT3608 ) were tested using PSpice for Ti from Texas Instruments.

Without soldering short contacts, the input voltage of MT3608 using SEPIC-CUK is 2V - 24V

The input voltage of XL6007E1 is 3.6V - 24V 

After soldering, it is almost 3.6V-24V. Pay attention to the withstand voltage of the input filter capacitor.

The inductor selection is the model on the schematic diagram. For details, please refer to ADI's "Improved Topology of Separated Power Supply Rails from a Single Input Voltage"

Using SEPIC-CUK+BOOST power topology

The MT3608 in the schematic diagram outputs ±15V, and the XL6007E1 outputs +60V. After common ground, it can output +75V.

XL6007E1’s output of 60V is almost the limit, MT3608 can output even more

The FB resistance calculation formula of MT3608 is Vout = Vref × (1 + R3/R4) where Vref = 0.6V

The first version is because MT3608 does not have an output capacitor → "The working principle of electronic components mainly depends on the magic smoke inside. Once it escapes, it will not work."

The current schematic and PCB have already added these two capacitors, feel free to use them.

The two voltage rail voltages generated by MT3608 will fluctuate somewhat

And the ripple is a bit big. If you have the conditions, you can try changing to SX1308. The word oscilloscope is a bit presbyopic.

Note: The withstand voltage of the capacitors C7 and C8 needs to be more than twice the output voltage of MT3608, which is about the output voltage × 3. Try to choose an mlcc. Tantalum capacitors need a larger withstand voltage.

For the input and output filter capacitors, just buy a few 1uF 1206 50V mlcc. Others can be purchased according to the BOM table on the schematic diagram. Use as appropriate.